First proficiency test for determination of NORM in contaminated soil from the oil field

The syrian Atomic Energy Commission in cooperation with the Arabic Atomic Energy Agency (AAEA) has initiated the first proficiency test exercise for determination of NORM in contaminated soil from the oil field. The soil sample was collected from one of the highly radioactively contaminated lagoons with production water in the Syrian oil fields, prepared, characterized and certified according to a standard procedure. Samples were dispatched to laboratories from eight Arab countries, viz. Kuwait, Egypt, Yemen, Tunisia, Jordan, Kingdom of Saudi Arabia, Libya and Syria. The results were evaluated using three statistical criteria; viz. z-Score, the Utest score and the relative bias. These statistical methods were used to evaluate the performance of each laboratory in addition to the overall evaluation for each radionuclide. This evaluation has indicated that 57% and 86% of the results passed the criteria set for precision and accuracy applied for this test in relation to 226Ra and 228Ra, respectively. These two radionuclides are considered to be the most important radionuclides in the oil industry. (author)